Capsule and lipopolysaccharide - Escherichia coli: Pathotypes and Principles of Pathogenesis - page 524

TABLE 17.1 Representative O- and K-antigen structures

Serotype Repeat unit structure Reference

O7 L'vov et al.,

1984

-3)- -Qui4NAc-(1-2)- -Man-(1-4)- -Gal-(1-3)- -GlcNAc-(1-
3

-Rha-(1

O8 -2)- α -Man-(1-2)- α -Man-(1-3)- β -Man-(1- Jansson et al.,

1985

O9a -2)- α -Man-(1-2)- α -Man-(1-3)- α -Man-(1-3)- α -Man-(1- Parolis et al.,

1986

O9 -2)-[ α -Man-(1-2)] 2 - α -Man-(1-3)- α -Man-(1-3)- α -Man-(1- Prehm et al.,

1976

O86 Andersson

et al., 1989

-4)- -Fuc-(1-2)- -Gal-(1-3)- -GalNAc-(1-3)- -GalNAc-(1-
3

-Gal-(1

O111 Kenne et al.,

1983

-Col-(1
3
-3)- -GlcNAc-(1-4)- -Glc-(1,4)- -Gal-(1-
6

-Col-(1

O157 -2)- α -PerNAc-(1-3)- α -Fuc-(1-4)- β -Glc-(1-3)- α -GalNAc-(1- Perry et al.,

1986

K1 -8)- α -Neu5Ac-(2- McGuire

et al., 1964

K4 Rodriguez

et al., 1988

-4)- -GlcA-(1-3)- -GlcNAc-(1-
3

-Fru-(1

K5 -4)- β -GlcA-(1-4)- α -GlcNAc-(1- Vann et al.,

1981

the repeat-unit domain) to the non-reducing end of the glycan (reviewed in
Cuthbertson et al., 2010 ). These residues may be alternative sugars or non-gly-
cose moieties and they not only prevent further elongation of the glycan, but are
also required to engage the ABC transporter for export across the inner mem-
brane. However, other O antigens in this pathway engage the ABC transporter
in the absence of any identifiable terminating group and coordination of the
activities of the O-PS elongating enzymes and the ABC transporter determine
O-PS chain length ( Cuthbertson et al., 2010 ).
The Lpt proteins, which span the inner and outer membranes as well as the
periplasm, are responsible for transport of the mature LPS. Given the heterogeneity